src/i18n.js

import Vue from 'vue';
import VueI18n from 'vue-i18n';

Vue.use(VueI18n);

function loadLocaleMessages() {
  const locales = require.context(
    './locales',
    true,
    /[A-Za-z0-9-_,\s]+\.json$/i
  );
  const messages = {};
  locales.keys().forEach(key => {
    const matched = key.match(/([A-Za-z0-9-_]+)\./i);
    if (matched && matched.length > 1) {
      const locale = matched[1];
      messages[locale] = locales(key);
    }
  });
  return messages;
}

export default new VueI18n({
  // default language is English
  locale: 'en',
  // locale messages with a message key that doesn't exist will fallback to English
  fallbackLocale: 'en',
  messages: loadLocaleMessages()
});